ERBB2 and metastatic neoplasm: The anti-HER2 paradigms for metastatic breast cancer have changed since the initiation of this study; pertuzumab is approved in combination with trastuzumab and docetaxel as first-line treatment for patients with HER2-positive metastatic breast cancer who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease, whereas TDM-1 is approved for patients with HER2-positive metastatic breast cancer previously treated with trastuzumab.